Publications of the Earthquake Investigation Committee in Foreign Languages Volume 20-21 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1903 edition. Excerpt: ...occupied the whole remainder of the.preliminary tremor, and which consisted of the following two displacements: --1st displacement = 1.2 mm, toward W, 2nd =1.7 E. The max. 2a and the average T of the superposed quick vibrations were respectively 0.7 mm and 1.6 sec The "principal portion," whose duration was 17m 3s, began with a well defined vibration of T--l sec, whose 1st displacement was directed toward W. The motion was most active for the 1st 5m 46s, during which time the amplitude remained on the whole nearly equal. During the earlier 2m 9s of this epoch, the motion consisted principally of 34 vibrations with an average T of 3.8 sec, of which the greatest motion of 3.15 mm took place lm 50s after the commencement of the principal portion. These were mixed up with vibrations whose averago T was 6.3 sec, and whose three maximum movements of 4.3, 3.6, and 3.8 mm occurred respectively Om 22s, lm 7s, and lm 38s, from the commencement of the principal portion. There were also more or less distinct traces of slow vibrations with an average T of 15.2 sec, whose max. 2a was 4.7 mm; the 1st displacement of the 1st vibration, whose T was 15.2 sec, being directed toward W. There were also quick superposed movements of T--2.1 sec, whose max. 2a was 2.3 mm. The subsequent motion became simpler on account of the lessening of quick vibrations, and began with 3 well defined movements which lasted 25.8 sec, and had an average T of 8.6 sec, the 3rd vibration having the greatest 2a of 4.35 mm. For the next 3m 15s, the average T was 6.1 sec, the two max.-a's of 3.6 and 2.7 mm having occurred respectively 3m 50s from the commencement of the principal portion and at the end of the most active part. The superposed vibrations...